Open source Over Boost Fuel Cut - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

ztan · 08-07-2015, 08:28 PM

***Use at your own risk.***

This implementation hijacks the speed limiting fuel cut routine and assesses MAP instead of vehicle speed.

Defined for A00G/A01G ROM: a single value in the speed limiting fuel cut routine is changed (from 0x58 to 0x5A) to get MAP loaded instead of speed and MAP limits are entered in place of speed limits. To clarify, no additional patch is needed for this modification besides the single value switch in the code - thanks to Subaru engineers who just lifted the speed limit rather than write new code.

Defs and test log with 1.35 Bar cut limit and 4400 RPM active.
First ramp showing MAP > 1.35, RPM < 4400: No fuel cut.
Second ramp showing MAP > 1.35, fuel cut when RPM hits 4400.
Third ramp showing RPM > 4400, fuel cut when MAP hits 1.35.

This is a neck-snapping hard fuel cut, but probably better than a blown engine due to major overboost. Haven't done extensive testing and you'll lose your speed limiter fuel cut if you apply this (default set to fuel cut over 500 km/h).

Def for A00G/A01G:

Code:

    
    <table name="Boost Limit (Fuel Cut) enable" storageaddress="66831" />
    <table name="Boost Limit (Fuel Cut)" storageaddress="10C540" />
    <table name="Boost Limit (Fuel Cut) Resume" storageaddress="10C550" />
    <table name="Boost Limit (RPM) Active" storageaddress="10C554" />
    
<!--<table name="Speed Limiting Enable (Fuel Cut)" storageaddress="10C540" />
    <table name="Speed Limiting Disable (Fuel Cut)" storageaddress="10C548" />
    
<table type="Switch" name="Boost Limit (Fuel Cut) enable" category="Miscellaneous - Limits" sizey="1">
      <description>Enable Boost Limit (Fuel Cut)</description>
      <state name="Enabled" data="5A" />
      <state name="Stock ROM" data="58" />
</table>
        
<table type="2D" name="Boost Limit (Fuel Cut)" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="4" userlevel="4">
      <scaling units="Manifold Abs Pressure Bar" expression="x*.001333224" to_byte="x/.001333224" format="#0.000" fineincrement=".001" coarseincrement="0.01" />
      <table type="Static Y Axis" name="Boost Limit Fuel Cut" sizey="4">
        <data>On Above</data>
        <data>On Above</data>
        <data>Off Below</data>
        <data>Off Below</data>
    </table>
          <description>These are the MAP values at which the boost limiter is engaged and disengaged. When engine speed is equal to or exceeds the 'On' value, fuel cut is active, after which, if engine speed drops below the 'Off' value, fueling is resumed.</description>
    </table>    

<table type="2D" name="Boost Limit (Fuel Cut) Resume" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="1" userlevel="4">
      <scaling units="Manifold Abs Pressure Bar" expression="x*.001333224" to_byte="x/.001333224" format="#0.000" fineincrement=".001" coarseincrement="0.01" />
      <table type="Static Y Axis" name="Boost Limit Fuel Resume (MAP)" sizey="1">
        <data>Below</data>
      </table>
      <description>After the boost limiter is engaged and engine speed drops below the 'Off' RPM, fueling will not resume until manifold pressure drops below this table's value.</description>
      </table>      
      
<table type="2D" name="Boost Limit (RPM) Active" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="1" userlevel="4">
      <scaling units="Engine Speed (RPM)" expression="x" to_byte="x" format="#" fineincrement="50" coarseincrement="100" />
      <table type="Static Y Axis" name="Boost Limit Active over" sizey="1">
        <data>Over</data>
      </table>
      <description>The boost limiter is active over this RPM</description>
      </table>

ztan · 08-07-2015, 09:15 PM

Just realized that I set my cut and resume values the wrong way around during that test and in the above example, cut would be > 1.3 Bar with resume < 1.35 Bar (no hysteresis with values set as above).

Shiv@Openflash · 08-08-2015, 03:33 AM

Quote:

Originally Posted by ztan

***Use at your own risk.***

This implementation hijacks the speed limiting fuel cut routine and assesses MAP instead of vehicle speed.

Defined for A01G ROM: a single value in the speed limiting fuel cut routine is changed (from 0x58 to 0x5A) to get MAP loaded instead of speed and MAP limits are entered in place of speed limits.

Defs and test log with 1.35 Bar cut limit and 4400 RPM active.
First ramp showing MAP > 1.35, RPM < 4400: No fuel cut.
Second ramp showing MAP > 1.35, fuel cut when RPM hits 4400.
Third ramp showing RPM > 4400, fuel cut when MAP hits 1.35.

This is a neck-snapping hard fuel cut, but probably better than a blown engine due to major overboost. Haven't done extensive testing and you'll lose your speed limiter fuel cut if you apply this (default set to fuel cut over 500 km/h).

Def for A01G:

Code:

    
    <table name="Boost Limit (Fuel Cut) enable" storageaddress="66831" />
    <table name="Boost Limit (Fuel Cut)" storageaddress="10C540" />
    <table name="Boost Limit (Fuel Cut) Resume" storageaddress="10C550" />
    <table name="Boost Limit (RPM) Active" storageaddress="10C554" />
    
<!--<table name="Speed Limiting Enable (Fuel Cut)" storageaddress="10C540" />
    <table name="Speed Limiting Disable (Fuel Cut)" storageaddress="10C548" />
    
<table type="Switch" name="Boost Limit (Fuel Cut) enable" category="Miscellaneous - Limits" sizey="1">
      <description>Enable Boost Limit (Fuel Cut)</description>
      <state name="Enabled" data="5A" />
      <state name="Stock ROM" data="58" />
</table>
        
<table type="2D" name="Boost Limit (Fuel Cut)" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="4" userlevel="4">
      <scaling units="Manifold Abs Pressure Bar" expression="x*.001333224" to_byte="x/.001333224" format="#0.000" fineincrement=".001" coarseincrement="0.01" />
      <table type="Static Y Axis" name="Boost Limit Fuel Cut" sizey="4">
        <data>On Above</data>
        <data>On Above</data>
        <data>Off Below</data>
        <data>Off Below</data>
    </table>
          <description>These are the MAP values at which the boost limiter is engaged and disengaged. When engine speed is equal to or exceeds the 'On' value, fuel cut is active, after which, if engine speed drops below the 'Off' value, fueling is resumed.</description>
    </table>    

<table type="2D" name="Boost Limit (Fuel Cut) Resume" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="1" userlevel="4">
      <scaling units="Manifold Abs Pressure Bar" expression="x*.001333224" to_byte="x/.001333224" format="#0.000" fineincrement=".001" coarseincrement="0.01" />
      <table type="Static Y Axis" name="Boost Limit Fuel Resume (MAP)" sizey="1">
        <data>Below</data>
      </table>
      <description>After the boost limiter is engaged and engine speed drops below the 'Off' RPM, fueling will not resume until manifold pressure drops below this table's value.</description>
      </table>      
      
<table type="2D" name="Boost Limit (RPM) Active" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="1" userlevel="4">
      <scaling units="Engine Speed (RPM)" expression="x" to_byte="x" format="#" fineincrement="50" coarseincrement="100" />
      <table type="Static Y Axis" name="Boost Limit Active over" sizey="1">
        <data>Over</data>
      </table>
      <description>The boost limiter is active over this RPM</description>
      </table>

Fantastic work!

Shiv@Openflash · 08-08-2015, 11:17 PM

You have email

ztan · 08-09-2015, 06:32 AM

I've sent Shiv addresses for OFT_B01C ROM to test (only for OFT 2.xx ROMs). If anyone else with FI running A00C or A01C ROM wants some addresses to test before general release, get in touch with me.

Also note above that I have defined MAP pressure for fuel cut rather than boost (MRP) pressure. Just so no-one gets ideas of running at 1.3 Bar Boost = 19psi Boost, I did my testing on low boost: 1.3 Bar MAP = 0.3 Bar Boost = 4.35 psi Boost.

Shiv@Openflash · 08-09-2015, 02:41 PM

Quote:

Originally Posted by ztan

I've sent Shiv addresses for OFT_B01C ROM to test (only for OFT 2.xx ROMs). If anyone else with FI running A00C or A01C ROM wants some addresses to test before general release, get in touch with me.

Also note above that I have defined MAP pressure for fuel cut rather than boost (MRP) pressure. Just so no-one gets ideas of running at 1.3 Bar Boost = 19psi Boost, I did my testing on low boost: 1.3 Bar MAP = 0.3 Bar Boost = 4.35 psi Boost.

Thank ztan, I'll be testing in our turbo car on Monday. Once again, fantastic work and big kudos on your desire to contribute to the open source community

ztan · 08-13-2015, 10:30 AM

Shiv: thanks for the recommendation.

Shiv@Openflash · 08-13-2015, 01:32 PM

Quote:

Originally Posted by ztan

Shiv: thanks for the recommendation.

Nice! That's all my wife's doing. I haven't been to India in 10+ years! Have a great time

Shiv@Openflash · 08-20-2015, 09:44 PM

ztan knocked it out of the park. I just tested his update in our turbo FRS and it works beautifully. So beautifully, that I'll be adding it to all OFT350 customer tunes. In the datalog below, I have the boost cut to set to 9psi:

http://datazap.me/u/shivvishnu/oft-z...=0&data=2-9-13

Great work ztan. The community appreciates it!

ztan · 08-24-2015, 05:19 AM

Quote:

Originally Posted by Shiv@Openflash

ztan knocked it out of the park. I just tested his update in our turbo FRS and it works beautifully. So beautifully, that I'll be adding it to all OFT350 customer tunes. In the datalog below, I have the boost cut to set to 9psi:

http://datazap.me/u/shivvishnu/oft-z...=0&data=2-9-13

Great work ztan. The community appreciates it!

For those of you on B01C, this is what I sent to Shiv:

Note that I have set this .xml description to "boost" pressure in psi over atmospheric. Use the descriptor at the top of the post if you work in absolute Bar.

B01C:

Code:

    
    <table name="Boost Limit (Fuel Cut) enable" storageaddress="69171" />    
    <table name="Boost Limit (Fuel Cut)" storageaddress="10E5EC" />
    <table name="Boost Limit (Fuel Cut) Resume" storageaddress="10E5FC" />
    <table name="Boost Limit (RPM) Active" storageaddress="10E600" />
    
    <table type="Switch" name="Boost Limit (Fuel Cut) enable" category="Miscellaneous - Limits" sizey="1">
      <description>Enable Boost Limit (Fuel Cut)</description>
      <state name="Enabled" data="5A" />
      <state name="Stock ROM" data="58" />
    </table>
    <table type="2D" name="Boost Limit (Fuel Cut)" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="4" userlevel="4">
      <scaling units="Manifold Pressure (psi relative sea level)" expression="(x-760)*.01933677" to_byte="(x/.01933677)+760" format="#0.00" fineincrement=".01" coarseincrement=".5" />
      <table type="Static Y Axis" name="Boost Limit Fuel Cut" sizey="4">
        <data>On Above</data>
        <data>On Above</data>
        <data>Off Below</data>
        <data>Off Below</data>
    </table>
      <description>These are the MAP values at which the boost limiter is engaged and disengaged. When engine speed is equal to or exceeds the 'On' value, fuel cut is active, after which, if engine speed drops below the 'Off' value, fueling is resumed.</description>
    </table>
        <table type="2D" name="Boost Limit (Fuel Cut) Resume" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="1" userlevel="4">
      <scaling units="Manifold Pressure (psi relative sea level)" expression="(x-760)*.01933677" to_byte="(x/.01933677)+760" format="#0.00" fineincrement=".01" coarseincrement=".5" />
      <table type="Static Y Axis" name="Boost Limit Fuel Resume (MAP)" sizey="1">
        <data>Below</data>
      </table>
      <description>After the boost limiter is engaged and engine speed drops below the 'Off' RPM, fueling will not resume until manifold pressure drops below this table's value.</description>
      </table>
        <table type="2D" name="Boost Limit (RPM) Active" category="Miscellaneous - Limits" storagetype="float" endian="little" sizey="1" userlevel="4">
      <scaling units="Engine Speed (RPM)" expression="x" to_byte="x" format="#" fineincrement="50" coarseincrement="100" />
      <table type="Static Y Axis" name="Boost Limit Active over" sizey="1">
        <data>Over</data>
      </table>
      <description>The boost limiter is active over this RPM</description>
      </table>

Grip Ronin · 09-04-2015, 10:19 PM

this is great im going to need to add this to the sbd tune. would the same codes work on a A00c rom?

ztan · 09-05-2015, 05:38 AM

Quote:

Originally Posted by Grip Ronin

this is great im going to need to add this to the sbd tune. would the same codes work on a A00c rom?

I don't think so, but I haven't checked A00C.
Send me a PM and we can work on pulling them for A00C.

ztan · 09-09-2015, 08:44 PM

Pulled on Grip Ronin's request for A00C/A01C, no feedback yet.

Can someone test and report on the following if you have FI and A00C or A01C (use one of the two .xml descriptors above):

Code:

<table name="Boost Limit (Fuel Cut) enable" storageaddress="68F71" />
<table name="Boost Limit (Fuel Cut)" storageaddress="10E600" />
<table name="Boost Limit (Fuel Cut) Resume" storageaddress="10E610" />
<table name="Boost Limit (RPM) Active" storageaddress="10E614" />

Grip Ronin · 10-04-2015, 02:54 PM

Quote:

Originally Posted by ztan

Pulled on Grip Ronin's request for A00C/A01C, no feedback yet.

Can someone test and report on the following if you have FI and A00C or A01C (use one of the two .xml descriptors above):

Code:

<table name="Boost Limit (Fuel Cut) enable" storageaddress="68F71" />
<table name="Boost Limit (Fuel Cut)" storageaddress="10E600" />
<table name="Boost Limit (Fuel Cut) Resume" storageaddress="10E610" />
<table name="Boost Limit (RPM) Active" storageaddress="10E614" />

ya turbos still in my living room. just finished porting the turbine housing and wg. still weeks away from install lol.

08-13-2015, 10:30 AM	#7
ztan Senior Member Join Date: Jul 2013 Drives: Toyota 86 Location: Gold Coast, Australia Posts: 311 Thanks: 44 Thanked 361 Times in 145 Posts Mentioned: 60 Post(s) Tagged: 0 Thread(s)	Shiv: thanks for the recommendation. Attached Images

09-04-2015, 10:19 PM	#11
Grip Ronin The Mechanic Join Date: Mar 2012 Drives: Civic Turbo,FR-S Location: NJ Posts: 928 Thanks: 130 Thanked 171 Times in 119 Posts Mentioned: 2 Post(s) Tagged: 1 Thread(s)	this is great im going to need to add this to the sbd tune. would the same codes work on a A00c rom? __________________ IG-Joey_Soul Progress Thread Ported billet 20G

09-09-2015, 08:44 PM	#13
ztan Senior Member Join Date: Jul 2013 Drives: Toyota 86 Location: Gold Coast, Australia Posts: 311 Thanks: 44 Thanked 361 Times in 145 Posts Mentioned: 60 Post(s) Tagged: 0 Thread(s)	Pulled on Grip Ronin's request for A00C/A01C, no feedback yet. Can someone test and report on the following if you have FI and A00C or A01C (use one of the two .xml descriptors above): Code: <table name="Boost Limit (Fuel Cut) enable" storageaddress="68F71" /> <table name="Boost Limit (Fuel Cut)" storageaddress="10E600" /> <table name="Boost Limit (Fuel Cut) Resume" storageaddress="10E610" /> <table name="Boost Limit (RPM) Active" storageaddress="10E614" />

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08-07-2015, 09:15 PM	#2
ztan Senior Member Join Date: Jul 2013 Drives: Toyota 86 Location: Gold Coast, Australia Posts: 311 Thanks: 44 Thanked 361 Times in 145 Posts Mentioned: 60 Post(s) Tagged: 0 Thread(s)	Just realized that I set my cut and resume values the wrong way around during that test and in the above example, cut would be > 1.3 Bar with resume < 1.35 Bar (no hysteresis with values set as above).

08-08-2015, 11:17 PM	#4
Shiv@Openflash Senior Member Join Date: Sep 2013 Drives: 2013 FRS Location: SF, CA Posts: 2,629 Thanks: 1,055 Thanked 5,470 Times in 1,494 Posts Mentioned: 605 Post(s) Tagged: 9 Thread(s)	You have email

08-09-2015, 06:32 AM	#5
ztan Senior Member Join Date: Jul 2013 Drives: Toyota 86 Location: Gold Coast, Australia Posts: 311 Thanks: 44 Thanked 361 Times in 145 Posts Mentioned: 60 Post(s) Tagged: 0 Thread(s)	I've sent Shiv addresses for OFT_B01C ROM to test (only for OFT 2.xx ROMs). If anyone else with FI running A00C or A01C ROM wants some addresses to test before general release, get in touch with me. Also note above that I have defined MAP pressure for fuel cut rather than boost (MRP) pressure. Just so no-one gets ideas of running at 1.3 Bar Boost = 19psi Boost, I did my testing on low boost: 1.3 Bar MAP = 0.3 Bar Boost = 4.35 psi Boost.

08-20-2015, 09:44 PM	#9
Shiv@Openflash Senior Member Join Date: Sep 2013 Drives: 2013 FRS Location: SF, CA Posts: 2,629 Thanks: 1,055 Thanked 5,470 Times in 1,494 Posts Mentioned: 605 Post(s) Tagged: 9 Thread(s)	ztan knocked it out of the park. I just tested his update in our turbo FRS and it works beautifully. So beautifully, that I'll be adding it to all OFT350 customer tunes. In the datalog below, I have the boost cut to set to 9psi: http://datazap.me/u/shivvishnu/oft-z...=0&data=2-9-13 Great work ztan. The community appreciates it!

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